Why is my nipple becoming sensitive?

I am a 23 yr male and for the past for days my nipple on the right side seems to be getting more and more senceitive not to mention the whole right side of my chest, side and back are getting the same way. My right side of my back seems to be getting slight pinching feelings along with my right side chest and I don't know what it could be because it seems like everyday its getting worse at thi rate it hurts to have a sirt on because it hurts my nipple. Can someone please tell me what it might be